SW Michigan Fruit Update
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Southwest Michigan, September 8, 2009

Mark Longstroth, Bill Shane, Diane Brown-Rytlewski

Weather

The weather has been cool with highs in the 70s and lows in the 40s and 50s.  No significant rain occurred but some early morning fog and misty rain provided some leaf wetness.  Rain at the end of August brought about two inches of water.  Most sites have fair to good soil moisture.  Some areas continue to be dry.  We continue to lag behind normal in heat units.  We are now about two weeks behind normal.  We are now about a week behind last year. 

Southwest Michigan Growing Degree Day Totals March 1 through September 7, 2009				Grapes, April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	3332	2871	2149	2113
Fennville:	3105	2655	1950	1925

You can find weather and IPM information for Southwest Michigan at the Enviroweather website. 

Insects

Japanese beetle numbers are low.  Asian ladybird beetles are present in fruit plantings.  Oriental fruit moth trap catches are up, signaling the flight of the third generation. 

Tree fruit

In Peaches, we are harvesting Cresthaven, PF25, Loring, Glowingstar, PF19-007, PF23, PF24-007, PF24C, Allstar, Blushing Star, Redkist, Baby Gold, and Redskin.  Quality continues to be good with relatively few split pits.  Summer pruning may be needed to increase red skin color of r older varieties such as Cresthaven.  Brown rot is common in some orchards and fungicide treatments for brown rot are needed as fruit color.  Tarnished plant bug and stinkbugs are common in orchards with broadleaf weeds. 

In Plums,harvest of NY9, Italian, Red Heart, and Vision is underway. Ripening plums should also be protected from brown rot.  Apple maggot is a problem in ripening plums.  Scout for damage from white apple or potato leafhoppers. 

In Apples, harvest of Gingergold, Williams Pride, Zestar, Mollies Delicious, Jonamac, McIntosh and Gala is underway.  Empires and Jonathans are being harvested for caramel apples.  The SW Michigan apple maturity report is being posted weekly on Wednesdays from now through early October at the SW Michigan Research and Extension Center web site fruit newsletters.  Sunscald-like symptoms are appearing on Gala.  Sooty blotch and flyspeck are relatively rare.  Codling moth trap catches have declined for most orchards and Oriental fruit moth trap catches are significant in some orchards.  Oriental fruit moth is generally the insect of most concern during the month of September in southwest Michigan.

In Pears,Bartlett harvest for direct market sales continues with the winter pears Anjou and Bosc also being picked.  Harrow Sweet harvest is expected next week, depending on the site and the market.   Growers should protect against the second generation of codling moth, which attacks pears just before harvest.  Pear scab, Fabraea leafspot and sooty blotch are the primary diseases of concern.

Small fruit

Blueberry harvest is essentially over.  Some growers are still harvesting Elliott.  Blueberry maggot and alternaria fruit rot are the primary problems for the remaining fields being harvested.  For more information see the Michigan Blueberry IPM Newsletter posted by Paul Jenkins at the Berry Entomology Lab.  Annemiek Schilder’s Lab is still collecting samples of blueberries with suspected virus or virus-like problems. Sample collections will continue through the first week in October.  Annemiek is also interested in plants with symptoms of blueberry stunt, caused by a phytoplasma.  Plants infected with stunt have bushy branches at the base of the plant, leaves with chlorotic edges and interveinal areas that cup downward, and fruit ripens late, or not at all.  Plant samples with virus symptoms can be sent to Jerri Gillett, at MSU.  Please phone or email Jerri at 517-355-7539 or gillett@msu.edu, for instructions on sending samples.  Growers can hear more about viruses at the Virus Update Meeting, September 24 at Trevor Nichols Research Complex near Fennville from 9 to noon.

 

In Grapes, harvest of Mars, Fredonia, Himrod, Vanessa, and Marquis are underway.  Grapes have been the fruit crop most affected by the cool 2009-growing season.  Niagara harvest is projected to begin around September 20-21^st and Concords in October. Soluble solids (sugar) content are lagging, with Niagara at 8 and Concord at 9. The diseases of greatest concern now are botrytis and downy mildew.  Wet conditions spread botrytis, so susceptible varieties should be protected at veraison and whenever soaking rains are conducive to the disease.  Low nighttime temperatures have been a common occurrence lately, resulting in extended periods of wet foliage and fruit in the morning.  This weather is favorable for the spread of downy mildew, so fungicides against downy mildew are required during the summer season when there are morning dews.  Growers should continue to watch for the third generation of grape berry moth, which is still active. . Stings and tunnels can be found on the fruit.  Japanese beetles numbers are declining.  See the most recent copy of Grape IPM Newsletter at the MSU Grape current conditions webpage. 

 

Fall raspberry and blackberry picking continues.  Raspberry varieties include: Jaclyn, Caroline and Polana. Fall Blackberry varieties being picked include: Chester, Triple Crown, Prime-Jan® and Prime-Jim®.  A significant disease of brambles in the fall is Botrytis fruit rot (gray mold).  Although the frequent morning dew and ground fog we’ve experienced are favorable for this disease, the temperatures have been cool.  The pathogen prefers temperatures closer to 70. Most fruit production is likely to wrap up by the end of the month.  Many diseases such as anthracnose, cane blight, rust and botrytis overwinter on infected canes.  Pruning out all old fruited canes and infected primocanes after harvest, removing it from the field and destroying it is an important part of disease management.